Conventionally, an image forming apparatus such as a Multi Function Peripheral (MFP) is used to form an image on a sheet (paper). For enabling the reuse of the sheet by erasing an image formed on the sheet, there exists a technique where an image is printed on the sheet using a coloring agent having a decoloring property such as ink containing a leuco dye.
A coloring agent having decoloring property is erased when the coloring agent is subjected to a high temperature. Accordingly, to reuse a sheet, the sheet is heated using an erasing device, thus erasing an image formed on the sheet. The erasing of an image formed on a sheet may also referred to as “decoloring” in the explanation made hereinafter.
In the erasing device, a platen roller and a heat source are arranged in an opposed manner with a sheet conveyance path interposed between the platen roller and the heat source. The sheet is heated by conveying the sheet between the platen roller and the heat source, thus erasing a coloring agent having decoloring property. A cooling fan for cooling the device is mounted downstream of the platen roller and the heat source. Accordingly, the sheet which is conveyed through a conveyance guide is cooled by air from the cooling fan.
However, the conventional device has a drawback that the sheet may not be efficiently cooled. A device for erasing an image on a sheet may also have a scanner for converting a printed content into electronic data before the sheet is decolored or for sorting a sheet on which a residual image is present after decoloring. However, when a temperature of the sheet is high at the time of conveying a sheet again to the scanner for sorting the remaining image after the sheet is decolored, toner on the sheet adheres to a glass surface of the scanner thus giving rise to a drawback that the quality of a scanned image is deteriorated.